White House Press Secretary Sarah Sanders tweeted that Barr's confirmation was a "victory for the rule of law."

Barr will be assuming the nation's top law enforcement position as the results of Mueller's probe are expected to land on his desk in a matter of weeks.

Democrats questioned at his confirmation hearing whether he would make public the results of Mueller's investigation, as Barr suggested that neither the Mueller report nor even a redacted version of it would be made public, but possibly only a summary written by the attorney general. The law requires only that Mueller transmit his report to the AG.

Barr also faced criticism from Democrats over an unsolicited memo he sent to the Justice Department last year in which he criticized part of the special counsel's probe as "fatally misconceived" and he was questioned about his views on executive power ability to be independent from Trump.

Barr, 68, who has been counsel at the Kirkland & Ellis law firm, served as attorney general under President George H.W. Bush from 1991 until 1993, following an 18-year civil service career that began at the CIA.

The new attorney general, nominated by Trump in December to replace Jeff Sessions, will be only the second person to hold the job twice. John Crittenden was the first, in the 19th century.